San Diego County pension officials are suing a 76-year-old retired sheriff’s captain, trying to recover nearly $500,000 in pension benefits mistakenly overpaid to him over 13 years.

The clerical error that allowed the overpayment was discovered in September as the San Diego County Employees Retirement Association prepared to release data on six-figure pensions as part of a public-records request the agency fought in court for nearly a year.

In a release, the pension agency said it attempted to negotiate with retired Sheriff’s Capt. John Burroughs of Fallbrook for eight months before suing on Friday.

The lawsuit claims the overpayments stretched from October 1999 to September 2011 and seeks $475,000 plus interest.

“When an overpayment is discovered, SDCERA must seek to correct it,” the release said. “Ultimately, overpaid monies are public funds and must be recovered to fund the retirement benefits as SDCERA’s fiduciary duty to its 37,000 members.”

Burroughs’ attorney, Michael Conger, said the agency isn’t taking responsibility for its mistake. Conger said Burroughs is very ill, paid most of the benefits in taxes, has no way of getting them back and didn’t know there was an error.

“SDCERA has never made us a settlement offer,” Conger said. “We offered to go to mediation. They didn’t even respond. The man’s not going to live forever and SDCERA knows it, and the tragedy is this is exacerbating his illness.”

The story of how the overpayments were made stretches back to 1988 and a divorce that ordered a 36 percent share of Burrough’s pension benefit be given to his former spouse after his retirement in March 1993 with 34 and a half years of service.

When Burroughs’ former wife died in July 1997, Burroughs sought restoration of his benefits and two years later reached an agreement with the pension system. The agency paid him a lump sum of $51,563 in back-benefits and restored his full monthly pension payment — and then some.

“We were working with an old mainframe payroll system that was not set up to handle these types of transactions. So this was handled using a benefit deduction,” pension system CEO Brian White said via email. “When the court ordered Burroughs’ full benefit reinstated ... the deduction previously paid to the former spouse was removed AND the amount was added back into the gross, resulting in a double correction and error.”

Conger said SDCERA assured the retiree at the time that his new benefit amount was correct.

“’We’re really sorry, this time we have it right,’” Conger said Burroughs was told. “And now all these years later they are saying, ‘Oops! We made a mistake.’”

According to SDCERA, the error remained undiscovered until September 2011. The agency was pulling information from its old mainframe and verifying its accuracy before fulfilling a records request filed by the California Foundation for Fiscal Responsibility.

The foundation sought the names, benefits and benefit calculation information for all pensioners receiving at least $100,000 per year. The pension system fought the July 2010 records request in court until August 2011, arguing that criminals would use the information to harm, harass or swindle its wealthy, elderly pensioners.

After the error was discovered, pension officials reverted Burroughs’ monthly benefit to its accurate amount, from $12,060 per month to $8,096 per month. After a cost of living adjustment, Burroughs now makes $8,339 per month, White said.

White said no other errors were found during the preparation of the records request. He said the agency has many systems in place to ensure benefit accuracy.

“All benefit calculations have been automated for several years. In addition, those calculations are verified by two people,” White said. “We also conduct internal audits of retiree benefits and our external auditors also do audits.”

Conger believes the error with Burroughs’ pension was not discovered when the agency fulfilled the records request, but was found many years earlier. Under the law, the agency had three years to file the lawsuit, Conger said.

Burroughs was not available for comment. Conger said his client was out of town.

White said Conger’s statements to The Watchdog are inaccurate. He said Burroughs was negotiating with SDCERA before Conger was hired in April, and then the negotiations stopped. White said Conger has never made a formal settlement offer.

“It is unfortunate that Mr. Conger chose not to affirmatively engage in settlement discussions when he was retained back in April, despite repeated requests by SDCERA’s counsel,” White said. “SDCERA has tried for eight months, since October 2011, to reach a resolution of this matter and did all it could to avoid litigation.”

White said SDCERA has taken full responsibility for the mistake. The agency’s Friday release noted that it was a public acknowledgment of the error that was made.

“Mr. Burroughs’ health, whatever it may be, does not excuse him in not returning the windfall he mistakenly received,” White said. “Mr. Burroughs’ unjust enrichment is the fundamental issue in this matter, and Mr. Conger can offer no reason why Mr. Burroughs should be allowed to keep money he does not dispute was mistakenly paid.”